1. Field of the Invention
The present invention relates to skeletal implants (such as dental implants) and more particularly to a coping screw used in making impressions of the area surrounding a dental implant, and a method for using the same.
2. Description of the Prior Art
Dental implants are used to provide a platform to which a dental prosthesis may be secured to underlying bone in the mandible or maxilla of a dental patient. A typical root form dental implant system employs a dental implant that is placed in a prepared site in the underlying bone. A disposable mount is used to provide a connection to an insertion tool used to place the implant into the bone. If the implant is a threaded implant, the mount is typically a removable extension of the implant that provides a hex nut-type suface for engagement with a socket used for screwing the implant into the prepared site. Once the implant is engaged in the site, the mount is removed and discarded. A cover screw is affixed to the top of the implant and the bone surrounding the prepared site is allowed to grow into the implant for several months, thereby securing the implant to the bone.
Once the surrounding bone has sufficiently engaged the implant, the cover screw is removed and an impression coping is affixed to the implant. An impression of the implant and the surrounding teeth is taken and a dental prosthesis is constructed using the impression as a model of the area of the patient's mouth surrounding the implant site.
One method of taking an impression is the "indirect" or "closed tray" method. With the indirect method, impression material is placed around the implant and allowed to set. Sometimes a "tray" is placed over the impression material before the impression material has set. Once it has set the tray an the impression material are removed from the patient's mouth, with the impression coping still affixed to the implant. The impression coping is removed from the implant and the gum surrounding the prepared site is allowed to heal. The impression is then used in making a model of the implant and the patient's mouth so that the prosthesis may be constructed. Although this method is convenient for the implantologist, it has the disadvantage of making it difficult for the prosthesis maker to precisely align the prosthesis with the implant and the abutment (a structure that extends from the implant to which the prosthesis is secured) during the prosthesis-making process.
Once made, the dental prosthesis is affixed to the abutment with cement, or other affixing means. Thus, the abutment acts as a platform for securing a dental prosthesis to the implant.